1668207643 has 4 divisors (see below), whose sum is σ = 1668908320. Its totient is φ = 1667506968.

The previous prime is 1668207617. The next prime is 1668207679. The reversal of 1668207643 is 3467028661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3467028661 = 6917 ⋅501233.

It is a cyclic number.

It is not a de Polignac number, because 1668207643 - 2⁹ = 1668207131 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1668207643.

It is not an unprimeable number, because it can be changed into a prime (1668208643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 346755 + ... + 351532.

It is an arithmetic number, because the mean of its divisors is an integer number (417227080).

Almost surely, 2^1668207643 is an apocalyptic number.

1668207643 is a deficient number, since it is larger than the sum of its proper divisors (700677).

1668207643 is an equidigital number, since it uses as much as digits as its factorization.

1668207643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 700676.

The product of its (nonzero) digits is 290304, while the sum is 43.

The square root of 1668207643 is about 40843.6977145802. The cubic root of 1668207643 is about 1185.9963948316.

The spelling of 1668207643 in words is "one billion, six hundred sixty-eight million, two hundred seven thousand, six hundred forty-three".